The present invention relates to a formazan compound, a method for dyeing using the same, and a cellulosic high molecular material dyed therewith.
The dianisidine type dye such as C.I.Direct Blue 200, 202 and 203 has been known as a dyestuff to dye a cellulosic high molecular material fast in blue and has been used on a large scale in textile dyeing industry and in paper manufacturing industry. However, in production and use of an dianisidine, which is a mother compound for the dye, a particular attention and restriction for use are inevitable because it is a prescribed chemical.
Various substitutes for dianisidine have been developed, but any products have not yet brought a satisfactory effect. For example, JP No.2510876 discloses a formazane type direct dye, which is disadvantageously inferior in fitness for dyeing at a high temperature and in fastness to washing. It is desired that there should be developed a blue dye that is safer for environmental protection and is more excellent in dyeing performance. The dye is also required to retain an affinity for a cellulose fiber even at a high temperature because the product obtained by blending a cellulose fiber with a polyester fiber is dyed at the high temperature.
Therefore, it is an important problem to develop the blue dye to meet the above requirements, in other words, a dye that can be synthesized without dianisidine compound used for the raw material and is suitable for dyeing a cellulosic high molecular material to provide the dyed product that has a high color value, a high build-up and various kinds of good fastness.
The present inventors made a diligent study to solve the above problem and, as a result, have arrived at the present invention.
The present invention relates to the followings:
1. A formazan compound represented by Formula (1) as shown below or the salt thereof, 
(In Formula (1), R1 is hydrogen, sulfo, hydroxy, chloro, methoxy, carboxyl or alkyl; either of R2 and R3 is hydrogen and the other is sulfo; X is morpholino, 2-hydroxyethylamino or bis(2-hydroxyethyl)amino; and Y is a phenylene diimino represented by Formula (2) as shown below) 
(In Formula (2), R4 is sulfo or carboxyl)
2. A formazan compound or the salt thereof according to the item 1, wherein R1 is hydrogen; either of R2 and R3 is hydrogen and the other is sulfo; X is morpholino, 2-hydroxyethylamino, or bis(2-hydroxyethyl)amino; and Y is a group represented by Formula (2) wherein the two imino groups bind to the phenylene group at their respective para-positions.
3. A formazan compound or the salt thereof according to the item 1, wherein R1 is hydrogen; R2 is hydrogen; R3 is sulfo; X is morpholino or bis(2-hydroxyethyl)amino; and Y is a group represented by Formula (2) wherein the two imino groups bind to the phenylene group at para-position.
4. A formazan compound or the salt thereof according to the item 1, wherein R1 is hydrogen; R2 is hydrogen; R3 is sulfo; X is morpholino; and Y is a group represented by Formula (2) wherein R4 is sulfo and the two imino groups bind to the phenylene group at para-position.
5. A method for dyeing a cellulosic high molecular material which is characterized by using the formazan compound or the salt thereof according to any one of the item 1 to 4.
6. A cellulosic high molecular material dyed with the formazan compound or the salt thereof according to any one of the item 1 to 4.
The novel formazan compound of the present invention is represented by Formula (1) as shown above. In Formula (1), the alkyl group for R1 includes a C1-C4 alkyl group such as methyl, ethyl, n-propyl and n-butyl. Methyl or ethyl is preferable. R1 is preferable to substitute at the 2-position or 4-position.
The typical examples of the novel formazan compounds of the present invention represented by Formula (1) as shown above are listed in Table 1. In the column Y, PAS is a group represented by Formula (2) wherein R4 is sulfo and the two imino groups bind to the phenylene group at para positions; PAK is a group represented by Formula (2) wherein R4 is carboxyl and the two imino groups bind to the phenylene group at para positions; MAS is a group represented by Formula (2) wherein R4 is sulfo and the two imino groups bind to the phenylene group at meta positions; and MAK is a group represented by Formula (2) wherein R4 is carboxyl and the two imino groups bind to the phenylene group at meta positions. When the two imino groups in Formula (2) bind to the phenylene group at para positions and when the two imino groups in Formula (2) bind to the phenylene group at meta positions, the respective chemical formula is shown in following Formula (2-1) and Formula (2-2)) repectively: 
In order to obtain a formazan compound of the present invention represented by Formula (1), the formazan amino compound represented by Formula (3) as shown below is at first synthesized by a process as described below for example:
An amino benzoic acid is diazotized to get the diazo product, from which the hydrazine is derived. 1 mol of the hydrazine is condensed with 1 mol of a benzaldehyde in the aqueous solution at 80-95xc2x0 C. to get the phenylhydrazone. The phenylhydrazone is coupled with 1 mol of the diazotized product of 6-acetylamino-2-aminophenol-4-sulfonic acid in the aqueous solution under the presence of soda ash at 0-5xc2x0 C. Then, 1-1.5 mol of copper sulfate or copper chloride is added to introduce copper into the coupling compound. The compound thus obtained is treated with a strong alkali at 60-90xc2x0 C. for 3-6 hours to hydrolyze the acetylamino group and the formazan amino compound represented by Formula (3) is obtained. 
(In Formula (3), R1, R2, and R3 show their respective same meanings as described above)
The formazan compound of Formula (1) is then synthesized through a process as described below for example.
1 mol of the formazan amino compound represented by Formula (3) is reacted with 1 mol of 2,4,6-trichloro-1,3,5-triazine at a pH of 6-8 at 0-10xc2x0 C. for 2-3 hours to get the first condensate. 2 mol of a primary condensate is then reacted with 1 mol of a diamine corresponding to Y at a pH of 6-9 at 50-65xc2x0 C. for 8-24 hours to get a secondary condensate. 1 mol of a secondary condensate is reacted with 2 mol of an amine corresponding to X at a pH of 6-9 at 80-95xc2x0 C. for 6-18 hours to get a tertiary condensate, that is, the formazan compound represented by Formula (1).
The formazan compound represented by Formula (1) of the present invention also can be synthesized through the following process.
2 mols of 2,4,6-trichloro-1,3,5-triazine are reacted with 1 mol of diamine corresponding to Y at a pH of 5-8 at 0-10xc2x0 C. for 2-4 hours to get the first condensate. 1 mol of a primary condensate is reacted with 2 mol of the formazan amino compound represented by Formula (3) at a pH of 6-9 at 50-65xc2x0 C. for 2-4 hours to get a secondary condensate. 1 mol of a secondary condensate is reacted with 2 mol of an amine corresponding to X at a pH of 6-9 at 80-95xc2x0 C. for 6-18 hours to get the formazan compound represented by Formula (1).
The formazan compound represented by Formula (1) thus synthesized is generally isolated as the sodium salt thereof by a conventional procedure, for example, by salting out with sodium chloride.
The compound represented by Formula (1) of the present convention may be used in any form of the free acid and the salt. The salt is preferably soluble in water. The salt includes an alkali metal salt, an alkaline earth metal salt, an alkyl amine salt (for example, a C1-C4 lower alkyl amine such as monomethyl amine and diethyl amine), an alkanol amine salt and an ammonium salt. The preferable salt includes an alkaline metal salt such as a sodium salt, a potassium salt and a lithium salt; and a C1-C3 alkanol amine salt such as a monoethanol amine salt, a diethanol amine salt, a triethanol amine salt, a monoisopropanol amine salt, diisopropanol amine salt and a triisopropanol amine salt.
Each the salt of Formula (1) as described above can be obtained, for example, by the following process.
A crystal of the sodium salt obtained by the method mentioned above is dissolved in water and the obtained solution is acidified by adding an acid, and then filtered if necessary. The cake thus obtained is again dissolved in water, followed by adding a base, for example, potassium hydroxide, lithium hydroxide, aqueous ammonia or an amine such as diethanol amine or triethanol amine to obtain the potassium salt, the lithium salt, the ammonium salt or an amine salt such as the diethanol amine salt and triethanol amine salt respectively. The formazan compound represented by Formula (1) may be a dried product obtained by conventional salting out or be a liquid product obtained by diluting or condensing the reaction solution to adjust the concentration.
The formazan compound represented by Formula (1) may be used as a direct dye to dye a natural or regenerated cellulosic high molecular material. The cellulosic high molecular material to dye includes a natural cellulose fiber such as cotton and hemp, a regenerated cellulose fiber such as rayon, a blended fiber product containing thereof, a paper and a pulp.
A dipping dyeing method, a printing dyeing method and a padding dyeing method are used for dyeing the natural or regenerated cellulose fiber, and the dipping dyeing method is the most preferable.
The natural or regenerated cellulose fiber may be dyed with the compound represented by Formula (1) of the present invention by a dipping. In that case, a material to dye is introduced in a dyeing bath at 40-50xc2x0 C. under the condition of a relatively large bath ratio, followed by elevating the dyeing bath temperature to 80-100xc2x0 C. gradually and keeping the temperature for 20-60 minutes to dye. Before the bath temperature reaches the actual dyeing temperature or after as the case may be, a neutral salt such as sodium chloride and sodium sulfate may be added to the bath so as to accelerate the absorption of the dyestuff.
A blended fiber product containing polyester fiber and rayon can be dyed by using a compound represented by the formula (1) together with a disperse dye in a single bath by a high temperature dyeing method at 120-130xc2x0 C., wherein the pH is preferably adjusted to a neutral or an alkaline range by a pH regulating agent. The compound represented by Formula (1) of the present invention does not lose the affinity for the blended fiber product even if it is used for dyeing at a high temperature. Furthermore, the compound, if it is used for dyeing in combination with a general-purpose yellow or red dyestuff, can bring a good dyeing reproducibility because of their uniform affinities for the fiber. The dyed product obtained by using the compound represented by Formula (1) of the present invention is excellent in light fastness, washing fastness and chlorine fastness, and has a high color value and a good build-up property.
Dyeing a paper or a pulp product with the compound of the present invention will be described below. A dyeing method of a paper product is mainly classified (I) an internal addition way in which a dyestuff is added to dye when the pulp is disintegrated or beaten to loose into pieces and (II) an external addition way in which a dye is added in the size press solution in size press process. Furthermore, an another method may be used, in which a surface of a paper is over-coated by a coating solution prepared with a dyestuff, an inorganic white pigment and a binder, etc. The formazan compound represented by Formula (1) is applicable for all the above ways. The most preferable for the compound is the internal addition way. In the internal addition way, the pulp is at first beaten until a beating degree of 400-490 c.c. by a pulper or a refiner to obtain a pulp slurry, then, 0.01-3.0% by weight (relative to the dried paper) of the formazan compound represented by Formula (1) is added to the slurry at a temperature of 10-40xc2x0 C. and, further, a usual filler, a sizing agent, a sulfuric acid band, a paper reinforcement and a binder which are conventionally used are added if necessary, followed by making paper and drying according to a conventional process to get a paper dyed with the formazan compound represented by Formula (1). The formazan compound represented by Formula (1) has an affinity for paper (a cellulosic high molecular material), and can provide the dyed paper with high color value and good fastness (light fastness).